Recently, a wireless communication system is widely developing to provide a communication system of various types such as audio, data and the like. In general, a wireless communication system corresponds to a multiple access system capable of supporting communication with multiple users by sharing an available system resource (bandwidth, transmit power and the like). Examples of the multiple access system include a CDMA (Code Division Multiple Access) system, an FDMA (Frequency Division Multiple Access) system, a TDMA (Time Division Multiple Access) system, an OFDMA (Orthogonal Frequency Division Multiple Access) system, an SC-FDMA (Single Carrier Frequency Division Multiple Access) system and the like.
A standard for a WLAN (wireless local area network) technology is developing by IEEE (institute of electrical and electronics engineers) 802.11 group. IEEE 802.11a and b use an unlicensed band on 2.4 GHz or 5 GHz, IEEE 802.11b provides transmission speed of 11 Mbps and IEEE 802.11a provides transmission speed of 54 Mbps. IEEE 802.11g provides transmission speed of 54 Mbps by applying OFDM (orthogonal frequency division multiplexing) on 2.4 GHz. IEEE 802.11n provides transmission speed of 300 Mbps by applying MIMO-OFDM (multiple input multiple output-orthogonal frequency division multiplexing). IEEE 802.11n supports a channel bandwidth up to 40 MHz. In this case, transmission speed can be provided as fast as 600 Mbps. IEEE 802.11p corresponds to a standard for supporting WAVE (wireless access in vehicular environments). For instance, 802.11p provides improvement necessary for supporting ITS (intelligent transportation systems). IEEE 802.11ai corresponds to a standard for supporting fast initial link setup of IEEE 802.11 station.
A DLS (direct link setup)-related protocol in wireless LAN environment according to IEEE 802.11e is used on the premise of a QBSS (quality BSS) supporting QoS (quality of service) supported by a BSS (basic service set). In the QBSS, not only a non-AP STA but also an AP corresponds to a QAP (quality AP) supporting QoS. Yet, in current commercialized wireless LAN environment (e.g., wireless LAN environment according to IEEE 802.11a/b/g etc.), although a non-AP STA corresponds to a QSTA (quality STA) supporting QoS, most of APs corresponds to a legacy AP incapable of supporting QoS. Consequently, in the current commercialized wireless LAN environment, there is a limit in that a QSTA is unable to use a DLS service.
In a recent situation that such a wireless short-range communication technology as Wi-Fi and the like is widely applied to a market, connection between devices is performed not only based on a local network but also based on direct connection between devices. One of technologies enabling devices to be directly connected is Wi-Fi Direct.
Wi-Fi Direct corresponds to a network connectivity standard technology describing up to operations of a link layer. Since there is no definition on a regulation or a standard for an application of a higher layer, it is difficult to have compatibility and consistency of an operation after Wi-Fi Direct devices are connected with each other. For this reason, such a standard technology including higher layer application technology as WFDS (Wi-Fi Direct service) is under discussion by WFA (Wi-Fi alliance).
The WFA has announced such a new standard for delivering data via a direct connection between mobile devices as Wi-Fi Direct. Hence, related industries are actively developing a technology for satisfying the Wi-Fi Direct standard. In a strict sense, the Wi-Fi Direct is a marketing terminology and corresponds to a brand name. A technology standard for the Wi-Fi Direct is commonly called Wi-Fi P2P (peer to peer). Hence, the present invention describing Wi-Fi-based P2P technology may be able to use Wi-Fi Direct and Wi-Fi P2P without any distinction. In a legacy Wi-Fi network, a user accesses the legacy Wi-Fi network via an AP (access point) and accesses the Internet to use a device on which Wi-Fi is mounted. A data communication method via direct connection between devices is also used in a legacy communication by some users in a manner of being mounted on a device (e.g., a cellular phone, a note PC, etc.) on which a wireless communication technology such as Bluetooth is mounted. Yet, according to the data communication method, transmission speed is slow and transmission distance is limited to within 10 m. In particular, when the data communication method is used for transmitting massive data or is used in environment at which many Bluetooth devices exist, there exists a technical limit in performance capable of being felt by a user.
Meanwhile, Wi-Fi P2P maintains most of functions of the legacy Wi-Fi standard and includes an additional part for supporting direct communication between devices. Hence, the Wi-Fi P2P can sufficiently utilize hardware and physical characteristics of a device on which a Wi-Fi chip is mounted and is able to provide device-to-device P2P communication by upgrading a software function only.
As widely known, the device on which the Wi-Fi chip is mounted is extending to various ranges including a note PC, a smartphone, a smart TV, a game console, a camera and the like. For the device, sufficient numbers of suppliers and technology development personnel have been formed. Yet, software development supporting the Wi-Fi P2P standard is not vitalized yet. This is because, although a Wi-Fi P2P standard is announced, related software capable of conveniently using the Wi-Fi P2P standard is not distributed.
There exists a device playing a role of an AP in a legacy infrastructure network in a P2P group. The device is called a P2P group owner (GO) in a P2P standard. Various P2P clients may exist on the basis of the P2P GO. One GO exists in a single P2P group only and all remaining devices become client devices.